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Paul 19 Jun 12 at 09:54	Annual Gas Load If I have calculated the heat loss for a building, how is this converted to an annual gas load? I have a heat loass of 171.6kW, based on 70w/m2 and a GIA of 2451m2. How can I detemine my Hourly and Annual Gas Load from this figure? I have been allocated the responsibility of determining the costs of bringing natural gas onto the site and National Grid application is asking for these loads. Thank You
Richard Walder 26 Jun 12 at 12:22	The "Hourly Load" will just be your peak kW load - don't forget to account for boiler efficiency and any other gas loads such as domestic hot water and catering if applicable. The annual load is normally not that important on the application unless it is particularly high. However, at the early stages I'd normally calculate it by developing a very rough profile along the following lines: - Calculate peak design day kWh (peak design load x operating hours) - For each month, calculate the average external air temp and use this to calculate a monthly average dT (internal T-average external T) - For each month, use this dT to calculate what % of peak dT the system is (e.g. if your peak design dT is 20C and your monthly dT is 10C, you would use 50%) - Multiply peak load x montly % dT x number of days in the month for each month - Sum it all together for annual kWh Hopefully that makes sense; it's very basic but you can fine tune it by incorporating night set back periods and so on and it's probably good enough for calculating an annual load for the application at the early stages.
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Mr

Paul
19 Jun 12 at 09:54

Annual Gas Load If I have calculated the heat loss for a building, how is this converted to an annual gas load? I have a heat loass of 171.6kW, based on 70w/m2 and a GIA of 2451m2. How can I detemine my Hourly and Annual Gas Load from this figure? I have been allocated the responsibility of determining the costs of bringing natural gas onto the site and National Grid application is asking for these loads. Thank You

Richard Walder
26 Jun 12 at 12:22

The "Hourly Load" will just be your peak kW load - don't forget to account for boiler efficiency and any other gas loads such as domestic hot water and catering if applicable.

The annual load is normally not that important on the application unless it is particularly high. However, at the early stages I'd normally calculate it by developing a very rough profile along the following lines:

- Calculate peak design day kWh (peak design load x operating hours) - For each month, calculate the average external air temp and use this to calculate a monthly average dT (internal T-average external T) - For each month, use this dT to calculate what % of peak dT the system is (e.g. if your peak design dT is 20C and your monthly dT is 10C, you would use 50%) - Multiply peak load x montly % dT x number of days in the month for each month - Sum it all together for annual kWh

Hopefully that makes sense; it's very basic but you can fine tune it by incorporating night set back periods and so on and it's probably good enough for calculating an annual load for the application at the early stages.

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